2.1 Channel Bluetooth Amplifier Board ZK-MT21 - 50W2 +100W DIY Audio

Our review of the 2.1 Channel Bluetooth Amplifier Board ZK-MT21 finds it best suited to DIY speaker builders and home theater tinkerers who need flexible inputs and tangible bass control. The single biggest reason to buy is its combination of Bluetooth 5.0 connectivity and a true 2.1 channel output of 2x50W plus 100W subwoofer power, which delivers impactful low end without requiring a separate amplifier for the sub. The board is practical, compact, and built for repeated use, and the included copper DC connectors and barrier terminals make wiring straightforward for hobbyists and installers.

Key Features

• Bluetooth 5.0: Reliable wireless pairing with a range up to about 49 ft unobstructed makes connecting phones or tablets simple for streaming audio.
• Dual Inputs: A 3.5mm AUX input lets you attach TVs, media players, or legacy sources when Bluetooth is not desired.
• 2.1 Output: The rated 2x50W + 100W configuration provides distinct left/right channels plus a dedicated subwoofer output for stronger bass impact.
• Treble and Bass Control: On-board tone knobs let you tailor sound layering and sub emphasis without external equalizers.
• Protection Features: Short-circuit, overcurrent, overheating, and reverse-connection protections help prevent damage during installation and heavy use.
• Robust Connectors: Copper DC connectors and barrier terminals handle higher current without overheating and include a DC head lead for easy hookup.

Who It's For

The board is ideal for DIY speaker builders upgrading bookshelf speakers, custom home theater projects that need a compact amplifier with sub output, and small commercial audio setups where wired and wireless inputs are both useful. Installers who appreciate on-board tone controls will like the quick ability to shape sound without adding extra hardware.

Those seeking a fully finished consumer receiver with remote control, a built-in power supply, or plug-and-play enclosure should look elsewhere; this product expects some familiarity with wiring and a separate power supply to be sourced and installed.

Pros & Cons

Pros

• Clear benefit from Bluetooth 5.0 plus AUX for versatile source options.
• Powerful 2.1 channel output that produces pronounced bass when paired with a suitable subwoofer.
• Built-in protection circuitry reduces risk during real-world use and installation.
• Quality copper connectors and barrier terminals support reliable high-current connections.

Cons

• Requires an external compatible power supply and basic wiring skills, so it is not a plug-and-play boxed unit.
• No remote control or built-in enclosure included, which may be inconvenient for some end users.

Specifications

Channel Configuration	2.1 channel
Maximum Output	2 x 50W + 100W
Wireless Standard	Bluetooth 5.0 (up to ~49 ft)
Inputs	Bluetooth and 3.5mm AUX
Protection	Short-circuit, overcurrent, overheating, reverse-connection
Connectors	Copper DC connectors, barrier terminals, DC head lead included

Our Verdict

The ZK-MT21 amplifier board is a strong value for DIYers and small home theater upgrades because it combines modern Bluetooth streaming with a true 2.1 output and on-board tone controls. It is not a finished consumer receiver, but for those willing to supply power and do basic wiring, it delivers reliable protection, solid connectors, and noticeable bass performance at an accessible price.

Frequently Asked Questions

Does it include a power supply?
No, the board includes a DC head lead but requires a separate compatible power supply; no adapter or battery is included.

Can I connect a TV directly?
Yes, you can use the 3.5mm AUX input for TV or media player audio when Bluetooth is not preferred.

Is the Bluetooth range long?
Bluetooth 5.0 provides up to about 49 ft unobstructed; walls and other obstacles will reduce that distance.